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정전기력 가진에 의한 외팔보형 탄소나노튜브 공진기의 비선형 동적 응답
김일광(Kim, Il-Kwang),이수일(Lee, Soo-Il) 한국소음진동공학회 2011 한국소음진동공학회 논문집 Vol.21 No.9
This paper predicted nonlinear dynamic responses of a cantilevered carbon nanotube(CNT) resonator incorporating the electrostatic forces and van der Waals interactions between the CNT cantilever and ground plane. The structural model of CNT includes geometric and inertial nonlinearities to investigate various phenomena of nonlinear responses of the CNT due to the electrostatic excitation. In order to solve this problem, we used Galerkin's approximation and the numerical integration techniques. As a result, the CNT nano-resonator shows the softening effect through saddle-node bifurcation near primary resonance frequency with increasing the applied AC and DC voltages. Also we can predict nonlinear secondary resonances such as superharmonic and subharmonic resonances. The superharmonic resonance of the nano-resonator is influenced by applied AC voltage. The period-doubling bifurcation leads to the subharmonic resonance which occurs when the nano-resonator is actuated by electrostatic forces as parametric excitation.
6,6-Dibromopenicillanic acid 1,1-Dioxide 분자내 탄소 6-위치 브롬기의 전극촉매 수소화반응과 전극반응기구
김일광,이영행,이채호,Il Kwang Kim,Young Haeng Lee,Chai Ho Lee 대한화학회 1991 대한화학회지 Vol.35 No.2
The electrochemical reduction of carbon-6-dibromo groups on 6,6-dibromo penicillanic acid 1,1-oxide(DBPA) was investigated by direct current, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. The irreversible two electrons transfer on the reductive debromination of each bromo group proceeded by EC,EC mechanism at the two electrode reduction steps(-0.48, -1.62 volts). The 6-bromo-PA and 6,6-dihydro-PA was synthesized by controlled potential electrolysis. Upon the basis of results on the products analysis and interpretation of polarograms obtained at various pH, electrochemical reaction mechanism was suggested. 6,6-dibromopenicillanic acid 1,1-oxide(DBPA)의 6위치 dibromo기의 전기화학적 환원을 direct current, differential pulse polarography, cyclic voltammetry, 조절전위 전기량법으로 연구하였다. DBPA 환원과정은 2단계-0.48, -1.62 volts)에서 모두 완전비가역으로 2전자씩 이동하는 EC, EC 반응기구로 진행하였다. 조절전위 전기분해를 이용하여 6-bromo-PA와 6,6-dihydro-PA를 단계적으로 합성하였으며, pH 변화에 다른 폴라로그램의 해석과 생성물 분석의 결과를 바탕으로 전기화학적 반응기구도 제안하였다.
정전기력 가진에 의한 외팔보형 탄소나노튜브 공진기의 비선형 동적 응답
김일광(Il Kwang Kim),이수일(Soo Il Lee) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.4
This paper predicted the dynamic behaviors of a cantilevered carbon nanotube(CNT) incorporating the electrostatic force, van der Waals interactions between the CNT and ground plane. The structural model of the CNT includes geometric and inertial nonlinearities for predicting various phenomena of nonlinear responses of the CNT due to the electrostatic force. In order to solve the problem, we used Galerkin’s approximation and the numerical integration techniques and as a result, we predicted characteristics of nonlinear response of nano resonator. The cantilevered CNT shows complex dynamic responses and instabilities due to the applied dc and ac voltages, and driving frequencies. The results investigated in this paper are helpful to the modeling of nanotube based electromechanical devices such as nano-resonators and nano-sensors.
1-Benzyl-4-Iodomethyl-2-Azetidinone의 합성과 Iodo기에 대한 전기화학적 환원반응
김일광,이영행,이채호,채규윤,김윤근,Kim Il Kwang,Lee Young Haeng,Lee Chai Ho,Chai Kyu Yun,Kim Yoon Geun 대한화학회 1991 대한화학회지 Vol.35 No.1
1-Benzyl-4-iodomethyl-2-azetidinone(BIMA)을 합성하여 iodomethyl기에 대한 전기화학적 환원을 direct current, differential pulse polarography, cyclic voltammetry 그리고 controlled potential coulometry 방법으로 연구하였다. BIMA의 환원과정은 1단계(-1.35 volts vs. Ag-AgCl)에서 완전비가역과 2전자이동후에 양성자가 첨가되는 EEC 반응기구로 진행되었으며 1-benzyl-4-methyl-2-azetidinone이 생성되었다. 양이온 계면활성제(cetyltrimethylammonium bromide)의 농도가 진하여질수록 양전위 이동이 있었으나 음이온 계면활성제(sodium lauryl sulfate)의 경우에는 2단계로 세분화되는 현상이 나타났다. pH변화에 따른 전극환원과정과 생성물 분석의 결과를 바탕으로 전기화학적 반응기구를 제안하였다. 1-Benzyl-4-iodomethyl-2-azetidinone(BIMA) was synthesized and its electrochemical reduction was investigated by direct current, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. The irreversible two electron transfer on reductive dehalogenation of iodo group proceeded to form 1-benzyl-4-methyl-2-azetidinone by EEC electrode reaction mechanism at the first reduction step(-1.35 volts vs. Ag-AgCl). The polarographic reduction waves separated into two reduction steps due to anionic surfactant (sodium lauryl sulfate) effects, while the waves were shifted to the positive potential as the concentration of cationic surfactant (cetyltrimethylammonium bromide) increased. Upon the basis of results on the product analysis and interpretation of polarogram with pH variable, EEC electrochemical reaction mechanism was suggested.
유리질 탄소전극에서 양극벗김 네모파 전압-전류법에 의한 생체내 미량 수은의 정량
김일광,천현자,정승일,백승화,한완수,Kim, Il Kwang,Chun, Hyun Ja,Jeong, Seung Il,Beck, Seung Hwa,Han, Wan Soo 대한화학회 2001 대한화학회지 Vol.45 No.4
The trace-level mercury in bio-materials has been determinated by the anodic stripping square wave voltammetry (ASSWV)-technique at glassy carbon electrode. Prior to the analysis, the bio-materials were digested with $HNO_3/H_2SO_4$ mixture and KMnO4 was added to complete an oxidation process of the mixture. The detection limit of the mercury varied greatly with deposition time, deposition potential, pH and stirring rate. When the deposition was carried out for 240 sec on 400 rpm stirring at -1.0 volts vs. Ag/AgCl, the detection limit was below 0.5 ppb ($2.5{\times}10^{-9}M$). The accumulated mercury was high in the kidney and liver, and low in the brain according to the determination of mercury accumulation for a white rat by this method. 생체시료에 함유된 미량수은을 유리질 탄소전극을 사용하는 양극 벗김 네모파 전압-전류법으로 정량하였다. 생체시료는 HNO3/H2SO4 산혼합용액으로 삭히고, KMnO4를 가하여 산화시켰다. 수은의 검출한계는 석출전위, 시 간, pH, 그리고 용액을 저어주는 속도 등에 크게 영향을 받았다. 1.0 volts vs. Ag/AgCl에서 400rpm으로 저어주면서 240 sec 동안 석출시켰을 경우, 검출한계는 0.5 ppb 이하였다. 흰쥐에 대한 수은의 생체 축적량은 신장과 간에서 높았고, 뇌에서는 매우 낮았다.
Co(Ⅱ)$(dimethyl bipyridine)_3(ClO_4)_2$의 전기화학적 성질과 산소환원에 대한 전극 촉매 효과
김일광,박종술,한완수,김윤근,전일철,Kim, Il Kwang,Park, Chong Sool,Han, Wan Soo,Kim, Youn Keun,Jeon, Il Cheol 대한화학회 1997 대한화학회지 Vol.41 No.8
Co$(dimethyl bipyridine)_3(ClO_4)_2$의 확산계수$(D_0)$와 전극반응속도상수$(K_0)$를 순환전압전류법과 대시간전류법으로 구하였다. 확산계수에 대한 용매, 농도, 주사속도 등의 영향과 반응속도상수에 대한 온도변화의 영향을 조사하였다. 25$^{\circ}C$에서 확산계수는 $5.54{\times}10^{-6 }cm^2/sec$이었고, 반응속도상수는 $2.39{\times}10^{-3 }/s$ 이었으며, 용매의 점도가 커질수록 봉우리전류값과 확산계수는 감소하였다. 반응속도상수에 대한 온도의 영향으로부터, ${\Delta}G^{\neq},\;{\Delta}H^{\neq},\;{\Delta}S$ 등의 열역학적 파라미터를 구하였다. 이 화합물은 $O_2$분자의 환원에서 봉우리전류를 크게 증가시키고, 환원전위를 양(+)전위방향으로 이동시키는 열역학적 전극촉매현상을 보였다. Diffusion Coefficient$(D_0)$ and electrode reaction rate Constant$(K_0)$ of Co$(dimethyl bipyridine)_3(ClO_4)_2$ were determined by cyclic voltammetry and chronoamperometry. It was also investigated that the effects of solvent, concentration, and scan rate, etc. on the diffusion coefficient and the temperature effect on the rate constant. The peak currents and diffusion coefficients were dcreased as increasing the viscosity of solvent. Diffusion coefficient was $5.54{\times}10^{-6 }cm^2/sec$ and the reaction rate constant was $2.39{\times}10^{-3 }/s$ at 25$^{\circ}C$. The thermodynamic parameters such as ${\Delta}G^{\neq},\;{\Delta}H^{\neq},\;and\;{\Delta}S$ were calculated from plotting the reaction rate constants versus the solution temperatures. This compound was shown the catalytic effect on the oxygen reduction that the reduction peak current of oxygen was greatly enhanced and the peak potential was shifted to +0.2 volt.